enum{N=200000000};
char prime[N+1];
void fill()
{
    int i,j;
    for(i=0;i<=N;i++)
        prime[i]=1;
    prime[0]=prime[1]=0;
    for(i=2;i*i<=N+1;i++)
        if(prime[i])
            for(j=i*i;j<=N;j+=i)
            prime[j]=0;

}

int gold(int n)
{
    int p;
    for(p=3;p<=n/2;p+=2)
    if(prime[p]&&prime[n-p])
        return 1;
    return 0;
}
int main()
{
   long long s=clock();
   fill();
   int start=6,end=N,n;
   for(n=start;n<=end;n+=2)
    if(!gold(n))
        puts("Congratulations!");
  long long e=clock();
  printf("%.3f\n",(e-s)/1000.0);
}
